Bench-scale synthesis and characterization of biodegradable aliphatic–aromatic random copolymers with 1,4-cyclohexanedimethanol units for blown film applications = 생분해성 지방족-방향족 공중합체의 1,4-싸이클로헥센디메틸렌 모노머 도입에 따른 블로운 필름 특성 변화에 관한 연구
The development of biodegradable packaging films can resolve environmental issues caused by plastic waste, but it still remains a great challenge to develop economically-feasible polymers that simultaneously balance robust mechanical properties, biodegradability and transparency. In this work, we describe the bench-scale synthesis (~1.5 kg) and blown film characterization of new biodegradable aliphatic–aromatic copolymers, poly(1,4-butylene-1,4-cyclohexanedimethylene carbonate-terephthalate)s (PBCCTs) with different molar ratios of two diol monomers, 1,4-cyclohexanedimethanol (CHDM) and 1,4-butandiol (BD), from 0:1 to 5:5 (CHDM:BD) to optimize the mechanical, optical, thermal properties, and biodegradability. The incorporation of CHDM units significantly impacted the thermal properties of the blown films from these copolymers; PBCCT films with 50 mol% CHDM content had a more amorphous and glassy character compared with the films with 0 mol% CHDM. And, PBCCT films with 30-50 % CHDM content exhibited superior mechanical properties (tear strength: 11.5 kgf /mm and tensile strength: 369 kgf/$cm^2$) and comparable transparency (haze: 16%) to those of non-degradable polyethylenes (PEs), the most commonly employed materials for packaging film applications. Taken together, the bench-scale synthesis of biodegradable polymers with suitable thermomechanical, optical, and permeability properties presented here showcases the potential of these materials as sustainable packaging materials.